package collection;

import java.util.ArrayList;
import java.util.Collection;

public class CollectionDemo {
    public static void main(String[] args){
        Collection c = new ArrayList();
        c.add(new Point(1,2));
        c.add(new Point(3,4));
        c.add(new Point(5,6));
        c.add(new Point(7,8));
        c.add(new Point(9,0));
        c.add(new Point(1,2));
        //[元素1.toString(),元素2.toString(),元素3.toString()...]
        System.out.println(c);


        /*
        boolean contains（Object o）：
        判断当前集合是否包含给定元素o
        判断依据是给定元素是否与当前集合存在equals()比较为true的情况
         */
        Point p = new Point(1,2);
        boolean contains = c.contains(p);
        System.out.println("是否包含："+contains);

        /*
        boolean remove(Obiect o)：-----一般都不接收boolean的结果
        从当前集合中删除与给顶元素
        若存在重复元素则只删除一次
         */
        c.remove(p);
        System.out.println(c);

        c.remove(p);
        System.out.println(c);

        //集合中存放的是元素的引用
        Collection cc = new ArrayList();
        Point pp = new Point(1,2);
        cc.add(pp);
        System.out.println("pp:"+pp);
        System.out.println("cc:"+cc);

        pp.setX(100);
        System.out.println("pp:"+pp);
        System.out.println("cc:"+cc);


        /*
        Collection c = new ArrayList();
        c.add("one");
        c.add("two");
        c.add("three");
        c.add("four");
        c.add("five");
        //集合重写了Object的toString()方法，返回格式如下：
        //【元素1.toString()，元素2.toString()，元素3.toString()...】
        System.out.println(c);//[one, two, three, four, five]

        System.out.println("size:"+c.size());//5，输出集合的元素个数
        //isEmpty()判断集合是否为空集
        System.out.println("是否为空集，"+c.isEmpty());

        c.clear();
        System.out.println("集合已清空");
        System.out.println(c);
        System.out.println("size"+c.size());
        System.out.println("是否为空集："+c.isEmpty());
         */
    }
}
